ComboBox Behavior Changed from Ext 2.x.x to 3.x.x

In Ext 2.3.0, the ComboBox examples in Examples\form\combos.html, combos.js, if I open the States combo and mouse over a selection or use the arrow keys to highlight a selection and I press the Tab key to blur the combo, the highlighted value is placed in the text box at the top of the combo and this value is available to the form submit. Also, If I enter a partial state name like "Al", "Alabama" and "Alaska" are displayed in the expanded area, with "Alabama" placed in the text area as the selection. If I mouse over "Alaska" or highlight it using the arrow key and then tab out of the combo, the field I highlighted ("Alaska") appears in the text area as the selected value. It too is available for the form submit. Finally, If I type in an entire value, like "Alabama", without using the expanded area, that value is available for the form submit.

This has changed in 3.x.x, and does not work correctly. Using the same files in the 3.1.1 distribution, if I open the States combo and mouse over a selection or use the arrow keys to highlight a selection and I press the Tab key to blur the combo, the value goes back to the default text value "Select a State..." in the text box at the top of the combo and no value is available to the form submit. Also, If I enter a partial state name like "Al", "Alabama" and "Alaska" are displayed in the expanded area, with "Alabama" placed in the text area as the selection. If I mouse over "Alaska" or highlight it using the arrow key and then tab out of the combo, the field I highlighted ("Alaska") DOES NOT appear in the text area as the selected value, but rather "Alabama" remains. "Alaska" is not available for the form submit. Finally, If I type in an entire value, like "Alabama", without using the expanded area, that value is NOT available for the form submit even though it is displayed in the text area.

This seems like something has been broken here. The behavior found in Ext 2.x.x is the correct and desired behavior.
Why would you change this?

This appears to be a true bug since, although there may be workarounds, it once worked and was supported by the Ext code base. What gives?